Piezoelectric substance, piezoelectric substance element, liquid discharge head, liquid discharge device and method for producing piezoelectric substance

Abstract

A piezoelectric substance has a multi-layer structure consisting of single crystal layers or uniaxial crystal layers of a perovskite oxide expressed by the general formula of ABO 3 in which a main component at the site (A) is Pb, and a main component at the site (B) includes at least three elements selected from the group consisting of Mg, Zn, Sc, In, Yb, Ni, Nb, Ti and Ta. The multi-layer structure comprises a first crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals; a second crystal phase layer having a different crystal structure from the crystal structure of the first crystal phase layer; and a boundary layer between the first crystal phase layer and the second crystal phase layer, and having a crystal structure gradually changing in a thickness direction of the layer.

1. A piezoelectric substance having a multi-layer structure comprising single crystal layers or uniaxial crystal layers of a perovskite oxide, expressed by a general formula of ABO 3  in which a main component at the site (A) is Pb, and a main component at the site (B) includes at least three elements selected from the group consisting of Mg, Zn, Sc, In, Yb, Ni, Nb, Ti and Ta, wherein the multi-layer structure comprises:
 a first crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals; 
 a second crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals, but different from the crystal structure of the first crystal phase; and 
 a boundary layer between the first crystal phase layer and the second crystal phase layer, and having a crystal structure gradually changing in a thickness direction of the layer. 
 
     
     
       2. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb km α lm ) xm (Mg mm Nb nm Ti om β pm ) ym O 3 , wherein the suffixes satisfy 1≦xm/ym<1.5, km+lm=1, 0.7≦km≦1, 0≦lm≦0.3, mm+nm+om+pm=1, 0.1<mm<0.3, 0.3<nm<0.5, 0.2<om<0.4 and 0≦pm<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Sc, In, Yb, Ni, Ta, Co, W, Fe, Sn or Zn. 
     
     
       3. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb kz α lz ) xz (Zn mz Nb nz Ti oz β pz ) yz O 3 , wherein the suffixes satisfy 1≦xz/yz<1.5, kz+lz=1, 0.7≦kz≦1, 0≦lz≦0.3, mz+nz+oz+pz=1, 0.2<mz<0.4, 0.5<nz<0.7, 0.05<oz <0.20 and 0≦pz<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Sc, In, Yb, Mg, Ta, Co, W, Fe, Sn or Ni. 
     
     
       4. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb kn α ln ) xn (Ni mn Nb nn Ti on β pn ) yn O 3 , wherein the suffixes satisfy 1≦xn/yn<1.5, kn+ln=1, 0.7≦kn≦1, 0≦ln≦0.3, mn+nn+on+pn=1, 0.1<mn<0.3, 0.3<nn<0.5, 0.3<on<0.5 and 0≦pn<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Sc, In, Yb, Mg, Ta, Co, W, Fe, Sn or Zn. 
     
     
       5. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb kt α lt ) xt (Sc mt Ta nt Ti ot β pt ) yt O 3 , wherein the suffixes satisfy 1≦xt/yt<1.5, kt+lt=1, 0.7≦kt≦1, 0≦lt≦0.3, mt+nt+ot+pt=1, 0.1<mt<0.4, 0.1<nt<0.4, 0.3<ot<0.5 and 0≦pt<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Nb, In, Yb, Mg, Ni, Co, W, Fe, Sn or Zn. 
     
     
       6. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb ks α ls ) xs (Sc ms Nb ns Ti os β ps ) ys O 3 , wherein the suffixes satisfy 1≦xs/ys<1.5, ks+ls=1, 0.7≦ks≦1, 0≦ls≦0.3, ms+ns+os+ps=1, 0.1<ms<0.4, 0.1<ns<0.4, 0.3<os<0.5 and 0≦ps<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Ta, In, Yb, Mg, Ni, Co, W, Fe, Sn or Zn. 
     
     
       7. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb ky α ly ) xy (Yb my Nb ny Ti oy β py ) yy O 3 , wherein the suffixes satisfy 1≦xy/yy<1.5, ky+ly=1, 0.7≦ky≦1, 0≦ly≦0.3, my+ny+oy+py=1, 0.1<my<0.4, 0.1<ny<0.4, 0.4<oy<0.6 and 0≦py<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Sc, In, Ta, Mg, Ni, Co, W, Fe, Sn or Zn. 
     
     
       8. The piezoelectric substance according to  claim 1 , wherein the ABO 3  of the perovskite oxide is expressed by (Pb ki α li ) xi (In mi Nb ni Ti oi β pi ) yi O 3 , wherein the suffixes satisfy 1≦xi/yi<1.5, ki+li=1, 0.7≦ki≦1, 0≦li≦0.3, mi+ni+oi+pi=1, 0.2<mi<0.4, 0.2<ni<0.4, 0.2<oi<0.5 and 0≦pi<0.3; α includes any element of La, Ca, Ba, Sr, Bi or Sb; and β includes any element of Pb, Sc, In, Yb, Mg, Ni, Co, W, Fe, Sn or Zn. 
     
     
       9. A piezoelectric substance element having a piezoelectric substance and a pair of electrodes, wherein the piezoelectric substance has a multi-layer structure, consisting of single crystal layers or uniaxial crystal layers of a perovskite oxide, expressed by a general formula of ABO 3  in which a main component at the site (A) is Pb, and a main component at the site (B) includes at least three elements selected from the group consisting of Mg, Zn, Sc, In, Yb, Ni, Nb, Ti and Ta, wherein the multi-layer structure comprises:
 a first crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals; 
 a second crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals, but different from the crystal structure of the first crystal phase; and 
 a boundary layer between the first crystal phase layer and the second crystal phase layer, and having a crystal structure gradually changing in a thickness direction of the layer. 
 
     
     
       10. A liquid discharge head which has separate liquid chambers each communicating with a nozzle and piezoelectric substance elements each including a piezoelectric substance and a pair of electrodes arranged so as to correspond to the separate liquid chambers, and discharges a liquid in the separate liquid chamber from the corresponding nozzle, wherein the piezoelectric substance has a multi-layer structure, consisting of single crystal layers or uniaxial crystal layers of a perovskite oxide, expressed by a general formula of ABO 3  in which a main component at the site (A) is Pb, and a main component at the site (B) includes at least three elements selected from the group consisting of Mg, Zn, Sc, In, Yb, Ni, Nb, Ti and Ta, wherein the multi-layer structure comprises:
 a first crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals; 
 a second crystal phase layer having any crystal structure which is selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals, but is different from the crystal structure of the first crystal phase layer; and 
 a boundary layer between the first crystal phase layer and the second crystal phase layer, and having a crystal structure gradually changing in a thickness direction of the layer. 
 
     
     
       11. A liquid discharge device having a liquid discharge head for discharging a liquid, wherein a piezoelectric substance element for generating energy for discharging the liquid has a piezoelectric substance and a pair of electrodes, wherein the piezoelectric substance has a multi-layer structure, consisting of single crystal layers or uniaxial crystal layers of a perovskite oxide, expressed by a general formula of ABO 3  in which a main component at the site (A) is Pb, and a main component at the site (B) includes at least three elements selected from the group consisting of Mg, Zn, Sc, In, Yb, Ni, Nb, Ti and Ta, wherein the multi-layer structure comprises:
 a first crystal phase layer having any crystal structure selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals; 
 a second crystal phase layer having any crystal structure which is selected from the group consisting of tetragonal, rhombohedral, pseudocubic, orthorhombic and monoclinic crystals, but is different from the crystal structure of the first crystal phase layer; and 
 a boundary layer between the first crystal phase layer and the second crystal phase layer, and having a crystal structure gradually changing in a thickness direction of the layer.